Service arrangements for textile machines which can repair yarn breaks as well as perform yarn package changes are known, for example, from German Patent Publication DE 38 01 965 A1 or European Patent Publication EP 0 106 809 B. In addition to a pneumatically or mechanically operating auxiliary yarn transport device, these service arrangements have special yarn spinning units as well as a package changing device with means for passing the finished packages to a transport device, and a gripper device for inserting empty tubes into the bobbin frame of the respective work station.
It is furthermore known to employ an endless transport device for delivering empty bobbins and removal of wound packages at the work stations of yarn winding textile machines. Such an endless transport device is represented in German Patent Publication DE 40 01 253 A1, which has a conveyor extending along the longitudinal extent of the textile machine disposed between the work stations along opposite sides of the machine. The conveyor has gondola-like carrier elements for transferring the wound packages and separate holders for receiving empty tubes.
A further development of the transport device known from German Patent Publication DE 40 01 253 A1 is described in the subsequently published German Patent 43 13 522.6 (which corresponds to U.S. Pat, No. 5, 495, 991). The bobbin-producing machine represented in this publication has two rows of work stations extending in the linear direction of the machine and a transport device arranged centrally between these rows. The transport device is designed as an endlessly circulating conveyor including a plurality of transport units combined into a transport chain, each having a transport receptacle freely accessible from above. The transport receptacles are designed in such a way that they can receive an empty tube as well as a package.
The unloading or loading of the transport units at the work stations of the textile machine is performed by means of an independent service arrangement movable along the machine. Among other things, the service arrangement has a tube gripper which can be directly controlled via a control device. When exchanging a finished package for an empty tube, the tube gripper first takes up the empty tube from the transport receptacle of the transport unit and transfers it into an intermediate position. The package is subsequently pushed into the transport receptacle of the transport unit positioned at the respective work station by additional manipulating elements arranged on the service arrangement, such as frame openers and bobbin ejectors. Thereafter the tube gripper delivers the empty tube to the bobbin frame of the respective work station. In the process, the transfer of the empty tube takes place in a predetermined bobbin frame position in which the tube support arms are lifted off the winding drum of the winding device.
The tube gripper of the service arrangement is embodied either as a telescopic gripper or a boom gripper which is rotatably fastened on a bracket disposed at a distance above the transport device.